What is the management approach for a common iliac artery aneurysm?

Management of Common Iliac Artery Aneurysms

Elective repair is recommended for common iliac artery aneurysms ≥3.5 cm in diameter to prevent rupture. 1, 2

Diagnosis and Surveillance

• Common iliac artery aneurysms frequently coexist with abdominal aortic aneurysms (AAAs) in 20-40% of cases 2, 3
• For aneurysms <3.0 cm, surveillance with ultrasound every 12 months is appropriate 3
• For aneurysms 3.0-3.4 cm, surveillance should be increased to every 6 months 3
• CT angiography is recommended when the aneurysm approaches the intervention threshold (≥3.5 cm) or for pre-intervention planning 3
• The median expansion rate of common iliac artery aneurysms is 0.29 cm/year, with hypertension predicting faster expansion (0.32 vs. 0.14 cm/year) 4

Indications for Intervention

• Elective repair is recommended for:
  • Asymptomatic common iliac artery aneurysms ≥3.5 cm 1, 2
  • Any symptomatic iliac aneurysm regardless of size 1, 2
• Rupture of iliac aneurysms at diameters <4 cm is rare, but the risk increases substantially above this threshold 2, 4
• No rupture of common iliac artery aneurysms <3.8 cm was observed in a large case series, supporting the 3.5 cm threshold for intervention 4

Treatment Options

Open Surgical Repair

• Indicated for patients who are good surgical candidates 1
• Reasonable for patients who cannot comply with long-term surveillance required after endovascular repair 1
• Associated with higher perioperative complications and longer hospital stays compared to endovascular approaches 4

Endovascular Repair (EVAR)

• First-line treatment for most anatomically suitable patients requiring common iliac artery aneurysm repair 2, 4
• Particularly beneficial for moderate to high-risk surgical candidates 1
• Requires mandatory long-term surveillance imaging to monitor for endoleaks and aneurysm sac stability 1, 2
• CT imaging recommended at 1 month and 12 months post-procedure, then annually if stable 2

Technical Considerations

• When treating common iliac artery aneurysms, preservation of at least one hypogastric (internal iliac) artery is strongly recommended to decrease the risk of pelvic ischemia 1, 2
• Exclusion of internal iliac arteries can lead to significant complications:
  • Buttock claudication (27% with unilateral exclusion, 36% with bilateral exclusion) 2
  • Erectile dysfunction (10% of men) 2
  • Bowel ischemia (rare, <1%) 2
• For patients with compressive symptoms or arteriovenous fistulas, open repair should be preferentially considered 4

Outcomes

• 30-day mortality: 1% for elective repairs vs. 27% for emergency repairs 4
• Similar 3-year outcomes between open repair and EVAR:
  • Secondary patency rates: 99.6% for open repair vs. 100% for EVAR 4
  • Freedom from reintervention: 83% for open repair vs. 69% for EVAR 4
  • Survival rates: 76% for open repair vs. 77% for EVAR 4

Risk Modification

• Smoking cessation is strongly advised for all patients with aneurysms to reduce expansion risk 2
• Beta-blockers may be considered to reduce the rate of aneurysm expansion 1, 2
• Control of hypertension is important as it predicts faster aneurysm expansion 4

Management Algorithm

1. For asymptomatic common iliac artery aneurysms:

   • <3.0 cm: Surveillance with ultrasound every 12 months 3
   • 3.0-3.4 cm: Surveillance with ultrasound every 6 months 3
   • ≥3.5 cm: Proceed to repair 1, 2

2. For symptomatic common iliac artery aneurysms:

   • Immediate repair regardless of size 1, 2

3. Treatment selection:

   • For anatomically suitable patients: EVAR as first-line treatment 2, 4
   • For patients unable to comply with surveillance: Open repair 1
   • For patients with compressive symptoms or arteriovenous fistulas: Open repair 4